AFAIK fuel is fuel, Asda doesn't have a refinery, neither does Sainsbury's or Morrison's or Tesco's. They all source fuel from the 'local' refinery. If you ever happen to spend any time outside one you'll notice that many different branded tankers come out and go in and you'll also notice that they don't have hundreds of different storage tanks for regular, premium of each fuel. That's because the fuel comes from the same source, the only difference is the additive and detergent package that's included and this is selected by the use of a card given to the tanker driver. He swipes the shell card, he get's fuel and the shell additive package, he swipes Asda's card and he gets fuel and the Asda detergent package. The exception to this is V Power which last I was told they stored on it's own.

I guess what i'm saying is the fuel itself is no different, the 'extras' that are included are what makes it different, shell even marketed the fuel saver as having added ingredients that got you x miles more per tank and i've usually run shell fuel as on anything set up to use 98RON+ it tends to feel smoother.

This man has it 100% correct. (I also used to work in a petrol station).

Bring back National Benzole.

You've just brought me back nearly 40 years Warrington Rd. station at Culcheth!

I kinda disagree. Either method over a period of time IS accurate.

As a one off, definitively not.

Please explain to me how filling up on the light is accurate using the £20 top up method? Before you try, please remember you're working to a fixed financial value of £20 worth of fuel, not a fixed volume so the volume your £20 buys will vary every time the fuel price changes and the price has varied by anything up to 10p in the last 5 weeks, so at one stage £20 would buy you 14.3 ltrs vs the 15.3 ltrs it buys today, using my mpg over the last 8k that's 9 miles extra. I don't have the details for diesel but it's pretty likely to be similar only with a greater number of extra miles.

The £20 fill up method is useless unless fuel prices are fixed, this is why we have mpg, it uses two fixed unit of distance against a fixed volume of fuel.

Only put morrisons diesel in my vrs once. Wont fill up there again. Fuel economy was way worse and was like someone had put a brick under accelerator. Use total diesel now and its loads better.

Only put morrisons diesel in my vrs once. Wont fill up there again. Fuel economy was way worse and was like someone had put a brick under accelerator. Use total diesel now and its loads better.

If you only did it once, how do you know it was the fuel? Is this occurance repeatable?

What exactly do you think they could do to the fuel to give it less power? DIesel has a certain amount of energy per litre and there is nothing you could put in it which would be cheaper than diesel which would reduce this energy content.

If you only did it once, how do you know it was the fuel? Is this occurance repeatable?

What exactly do you think they could do to the fuel to give it less power? DIesel has a certain amount of energy per litre and there is nothing you could put in it which would be cheaper than diesel which would reduce this energy content.

i could tell the difference straight away, only went there because someone give us a voucher. never again

hahahaha, yeah measuring £20 of fuel lasts xx amount of miles is hardly the most accurate way of doing it.

i could tell the difference straight away, only went there because someone give us a voucher. never again

It takes many km for the new fuel in the tank to reach the engine. If you felt a difference immediately, it was definitely something else.

The light method is accurate, each time I fill I record the price etc so I know what litres I'm getting to the pounds im spending and use that for my calculations. Yes as the price rises and falls I get more and less for the £20 but that still doesn't change the fact that When I calculate I use the volume of fuel to find mpg, I'm not using the £20 in the equation.

PLACEBO!!!!

My last tank of diesel was from Tesco and the car averaged 47.8mpg on that tank

I don't really know why almost everybody are in arms about Tesco diesel. I've been using my local for over 5 years, I am not Michael Schumacher on the road but on a motorway I am steady 65/70, in town never had someone being unhappy behind me, I am driving with the flow and I never ever had less than 47 MPG for a tank. Last summer I had to drive to London and back in a day so I was driving hard and fast and even then my average for the whole trip (over 900 miles) was 48MPG. Over the last 5+ years using 95% of the time the local Tesco my average for this period is above 55MPG. I don't know how you driving guys but there is no way by changing to Tesco diesel for one tank (as majority are stating) could drop the MPG by 7 to 10 miles as some of you are claiming. If I punch the GO pedal my Fabia is as quick as anything else on the road.

Just shove some Miller's Diesel EcoMax in to boggo supermarket diesel, has much the same effect as BP Ultimate or Shell V-power but it only cost about a quid extra a tank.

Whats the point in buying Supermarket Fuel,then paying extra for an additive? You might as well buy a Better Quality Diesel in the first place, which doesnt need an additive !!

Why do you think that?

I just seem to get more mpg out of the car when I use it

I'm with Padrino on this. 50k on my vrs in 2 1/2 years using supermarket fuel and the average consumption has always been over 55mpg according to the computer.

Whats the point in buying Supermarket Fuel,then paying extra for an additive? You might as well buy a Better Quality Diesel in the first place, which doesnt need an additive !!

The point is, there is no difference in diesel quality. It all comes from the same dead forests and is all processed through the same refineries. Unless it comes to you in rusty 44 gallon drums mixed with water, there is no significant difference.

Until the extra additives are added in the branded fuels. I`v used all different fuels, the only thing I notice is a little less smoke with shell/bp diesel. As said, by the time you`ve added millers into a tank of tesco fuel you might as well just buy the branded stuff with it in already lol.

The older of my 2 Fabs has 171k and has pretty much ran on Sainsburys and Tescos fuel since 30k

Until the extra additives are added in the branded fuels. I`v used all different fuels, the only thing I notice is a little less smoke with shell/bp diesel. As said, by the time you`ve added millers into a tank of tesco fuel you might as well just buy the branded stuff with it in already lol.

I've never used additives and never seen the need.

If you are getting any smoke something else is wrong. Smoke is from the lowest air/fuel ratio of your engine, not the brand of fuel.

Its obvious innit. Just look at the globe. Uphill all the way there and downhill on the way back.

I did convince my ex that this was true...

My car is running tip top thanks, gets a regular once over at Unit 18 and run healthy figures on the dyno. I`m not talking night and day difference just slightly cleaner with decent fuel. I`m not the only person to notice, others on here have in the past as has my dad in his Mitsibushi L200.

If you're trying to compare the efficiency of different suppliers fuels you'll need to just use the on board trip computer - otherwise inaccuracies in the metering devices of the suppliers will swamp the measurement you're trying to make.

If you're trying to compare the efficiency of different suppliers fuels you'll need to just use the on board trip computer - otherwise inaccuracies in the metering devices of the suppliers will swamp the measurement you're trying to make.

More than that. You need to get rid of the human behind the wheel. That has far more influence on consumption than whether you fill up with Asda or Shell.

like most people are saying,supermarket fuel is about the same as the branded stuff alot of it is our mind playing tricks with us,we assume because it's supermarket fuel it must be rubbish,its like cornflakes for instance kelloggs versus supermarket value brand,they are eaxactly the same just in different packaging,tesco dont make cornflakes nor do they make fuel.i have used all sorts of diesel in my vrs and they are all about the same,i am currently using tesco fuel and i am getting on average 56mpg on a 21 mile commute to work very pleased with that and no excessive smoke and good performance,and the added bonus of clubcard points which has just allowed me to purchase a ticket for thorpe park(usaully costing £42.50) for £7.50 in vouchers bargain,fuel is costing everyone a arm and a leg at the moment so we might as well get something back for it.

The light method is accurate, each time I fill I record the price etc so I know what litres I'm getting to the pounds im spending and use that for my calculations. Yes as the price rises and falls I get more and less for the £20 but that still doesn't change the fact that When I calculate I use the volume of fuel to find mpg, I'm not using the £20 in the equation.

So in other words you don't use the 'xxx miles for £20' that the op posted and I disagreed with, you calculate distance against volume like the rest of us to calculate mpg. That's not the same as the op who stated he got xxx miles from a £20 fill up from the light and used this as the basis of comparison.

Even using the light is flawed, the odds of having a petrol station next to you at the exact moment the light comes on aren't great, the senders position changes relative to the car's motion, the fuel expands based on ambient temps and pump return. To compare a brimmed vented fill of fuel at a consistent cool temperature (thermal change a few feet below the surface is quite minimal) against a partial fill done using an inaccurate measure use yet even with your method you still think partial fills calculated against the fuel sender's estimates are consistent and accurate vs say a vented fill? While not as variable as the op you're still not getting an accurate figure. For example my non vented petrol fill has yielded circa 35 miles (7mpg up on average) more thanks to the warm weather this time round.